The Brazil Nut Tree, Bertholletia Excels (N = 17), Is

The Brazil nut tree, Bertholletia excels (n = 17) , is native to tropical rain forests of South America. It is a hardwood tree that can grow to over 50 metres tall, a source of high-quality timber, and a favourite nesting site for harpy eagles. As the rainy season ends, tough-walled fruits, each containing 8-25 seeds (Brazil nuts) , fall to the forest floor. Brazil nuts are composed primarily of endosperm. About $50 million worth of nuts are harvested each year. Scientists have discovered that the pale yellow flowers of Brazil nut trees cannot fertilise themselves and admit only female orchid bees as pollinators. The agouti (Dasyprocta spp.) , a cat-sized rodent, is the only animal with teeth strong enough to crack the hard wall of Brazil nut fruits. It typically eats some of the seeds, buries others, and leaves still others inside the fruit, which moisture can then enter and allow the remaining seeds to germinate.
If a female orchid bee has just left a Brazil nut tree with nectar in her stomach, and if she visits another flower on a different Brazil nut tree, what is the sequence in which the following events should occur?

A) pollination, pollen tube emerges from pollen grain, pollen tube enters micropyle, double fertilisation
B) pollination, pollen tube enters micropyle, pollen tube emerges from pollen grain, double fertilisation
C) pollen tube emerges from pollen grain, pollination, pollen tube enters micropyle, double fertilisation
D) pollen tube enters micropyle, pollen tube emerges from pollen grain, pollination, double fertilisation

Correct Answer:

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